Where are you?
In general, if you are not instrument rated, you cannot legally log ANY instrument time when solo in an aircraft. Also, if you are not IFR, how could you log instrument time without a safety pilot?
In the US, FAR 61.51. says:
(b) Logbook entries. For the purposes of meeting the requirements of paragraph (a) of this section, each person must enter the following information for each flight or lesson logged:
(1) General—
(i) Date.
(ii) Total flight time or lesson time.
(iii) Location where the aircraft departed and arrived, or for lessons in a flight simulator or flight training device, the location where the lesson occurred.
(iv) Type and identification of aircraft, flight simulator, flight training device, or aviation training device, as appropriate.
(v) The name of a safety pilot, if required by §91.109 of this chapter.
(2) Type of pilot experience or training—
(i) Solo.
(ii) Pilot in command.
(iii) Second in command.
(iv) Flight and ground training received from an authorized instructor.
(v) Training received in a flight simulator, flight training device, or aviation training device from an authorized instructor.
(3) Conditions of flight—
(i) Day or night.
(ii) Actual instrument.
(iii) Simulated instrument conditions in flight, a flight simulator, flight training device, or aviation training device.
and FAR 91.109.c says:
(c) No person may operate a civil aircraft in simulated instrument flight unless—
(1) The other control seat is occupied by a safety pilot who possesses at least a private pilot certificate with category and class ratings appropriate to the aircraft being flown.
(2) The safety pilot has adequate vision forward and to each side of the aircraft, or a competent observer in the aircraft adequately supplements the vision of the safety pilot; and
(3) Except in the case of lighter-than-air aircraft, that aircraft is equipped with fully functioning dual controls. However, simulated instrument flight may be conducted in a single-engine airplane, equipped with a single, functioning, throwover control wheel, in place of fixed, dual controls of the elevator and ailerons, when—
(i) The safety pilot has determined that the flight can be conducted safely; and
(ii) The person manipulating the controls has at least a private pilot certificate with appropriate category and class ratings.
Of course, a competent flight instructor would know where to find the applicable regulations...